Thermostat with bypass valve

Abstract

A choke-type thermostat is provided with a bypass valve. The inventive thermostat has a pliable valve member which prevents flow to an engine coolant bypass when the thermostat is in the completely open position in regards to an engine radiator outlet. Valving of the engine coolant bypass provides maximum flow to the radiator outlet when the thermostat is in the open position. Since the engine bypass is valved off by the thermostat when the thermostat is in the open position the diameter of the engine coolant bypass may be increased therefore allowing increased flow therethrough when the thermostat is in a closed position.

What is claimed is: 
     
       1. A choke-type thermostat for selectively connecting a fluid inlet with a first fluid outlet and a secondary fluid outlet comprising: a valve set separating said inlet and said first outlet;   a thermal elongating valve pin;   a rigid valve choke attached to said valve pin for making sealing contact with said valve seat at a first predetermined length of said valve pin; and   an elastomeric valve, fixedly attached to and surrounding said valve choke and projecting from said valve choke in a direction opposite said valve seat to a distal end disposed to axially engage structure surrounding said secondary outlet for sealing off said secondary outlet at a second predetermined length of said valve pin, said rigid valve choke remaining free from contact with said structure surrounding said fluid outlet.   
     
     
       2. A thermostat described in claim 1 wherein said elastomeric valve is attached to a metal band, said band being attached to said choke. 
     
     
       3. In combination with an internal combustion engine having structure defining respectively an engine fluid inlet, a heat exchanger outlet, and a heat exchanger bypass outlet, a choke-type thermostat comprising: a valve seat separating said inlet and said heat exchanger outlet;   a thermal elongating valve pin disposed along the axis of said valve seat in contacting relation therewith;   a first rigid cup-shaped valve choke attached to said valve pin for axial movement therewith and making sealing contact with said valve seat at a first predetermined length of said valve pin; and   a sleeve-like elastomeric valve attached to and disposed about the axial periphery of said valve choke and projecting from said valve choke in a direction opposite said valve seat to a distal end of circular section, said elastomeric valve being movablewith said choke causing said distal end to axially engage structure surrounding said bypass outlet to seal off said bypass outlet at a second predetermined length of said valve pin, said rigid valve choke remaining free from contact with said structure surrounding said bypass outlet.   
     
     
       4. The invention described in claim 1 and said bypass outlet structure being inwardly tapered into said outlet, said distal end of said elastomeric valve contacting the tapered portion. 
     
     
       5. A thermostat described in claim 3 wherein said elastomeric valve isattached to a metal band, said band being attached to said choke. 
     
     
       6. A choke-type thermostat adapted for selectively connecting an engine fluid inlet with a first fluid outlet and a secondary fluid outlet, said inlets and outlets defined by surrounding structure of an engine, comprising: a valve seat separating said inlet and said first outlet;   a thermal elongating valve pin;   a metal valve choke attached to said valve pin for making sealing contact with said valve seat to seal off said first outlet at a first predetermined length of said valve pin; and   an elastomeric valve surrounding said valve choke being operatively connected to said valve pin and making sealing contact with said valve seat at an end of said elastomeric valve adjacent said first outlet at a second predetermined length of said valve pin: and said elastomeric valve having a second end disposed to engage structure surrounding said secondary outlet for sealing off said secondary outlet at an end of said elastomeric valve opposite said valve seat at a third predetermined length of said valve pin, said rigid valve choke remaining free from contact with said structure surrounding said secondary outlet.   
     
     
       7. A thermostat described in claim 6 wherein said elastomeric valve is attached to a metal band said band being attached to said choke. 
     
     
       8. In combination with an internal combustion engine having structure defining respectively an engine fluid inlet, a heat exchanger outlet, and a heat exchanger bypass outlet, a choke-type thermostat comprising: a valve seat separating said inlet and said heat exchanger outlet;   a thermal elongating valve pin;   a rigid metal valve choke attached to said valve pin for making sealing contact with said valve seat at a first predetermined length of said valve pin; and   a sleeve-like elastomeric valve fixedly attached to and surrounding said valve choke and moving axially therewith to make sealing contact with said valve seat at a first end of said elastomeric valve adjacent said valve seat, and said elastomeric valve projecting axially away from said valve seat beyond said rigid metal valve choke to second end disposed to axially engage the structure surrounding said bypass outlet for sealing off said bypass outlet at an end of said elastomeric valve opposite said valve seat at a second predetermined length of said valve pin, said rigid metal valve choke remaing free from contact with said structure surrounding said bypass outlet.   
     
     
       9. The ivnention described in claim 8 wherein said elastomeric valve is attached to a metal band, said band being attached to said choke. 
     
     
       10. The invention described in claim 7 and said structuring defining said bypass outlet having a tapered surface engaging said elastomeric valve at said third predetermined length.